Emergency Response Information: High Pressure Gas, Steel (19.1)

Emergency Response Information: High Pressure Gas, Steel (19.1)

Description of Key Area

This key area pertains to the availability of appropriate
information resources needed by first responders to potential emergencies
(e.g., accidents) involving hydrogen stored and transported as a compressed gas
in steel cylinders. The emergency response information must be applicable to
tube trailers and/or any other compressed hydrogen steel cylinder packaging. In
particular, the emergency response information resources must apply to
operations such as the transfer of hydrogen from tube trailers to stationary
pressure vessels at vehicle fueling stations, temporary parking of tube
trailers to provide the hydrogen source at a fueling station, delivery of
hydrogen-filled steel cylinders to fueling stations, and the use of hydrogen
mobile fuelers with steel pressure vessels.

Discussion of Criticality

This key area will be critical if hydrogen fueling infrastructures
evolve that utilize hydrogen transported as a compressed gas in steel
cylinders. Examples include hydrogen transported in tube trailers from central
production plants to fueling stations (with the gas transferred to permanently
installed high-pressure vessels at the fueling station, or, as is more common,
parking of the tube trailer at the fueling station to serve as a temporary gas
supply) and mobile fuelers (some of which utilize compressed hydrogen stored
in steel cylinders). Both of these examples are in common use at this time to
support hydrogen-fueled vehicle demonstration projects. However, neither of
these infrastructure scenarios are economically viable, nor are they likely to
be part of a widespread hydrogen-fueled vehicle deployment scenario. They are
not economically viable because, for example, a truck-transported tube trailer
(which can hold up to 350 kg (772 lb) of hydrogen at up to 21.4 MPa (3100 psi))
consumes more energy than it delivers for distances greater than roughly 1610
km (1000 miles).

As discussed below, emergency response resources applicable to
accidents involving compressed hydrogen steel pressure vessels (e.g., as used
in tube trailers) are well developed for current applications, which are
generally limited to restricted-access industrial sites and trained personnel.
These same resources are probably appropriate and adequate for supporting
current tests and demonstrations of hydrogen vehicles, which are few in number,
have limited access, and are closely managed by trained personnel. A possible
exception may be associated with current and future use of mobile fueling
stations that store hydrogen in steel vessels. These units involve a relatively
unusual combination of components (e.g., unlike tube trailers, they are not addressed
specifically in the DOT ERG2004) and their application straddles two
jurisdictions (i.e., DOT when they are transported on highways and OSHA/local
AHJs when they are parked and operated as vehicle fueling stations).

If hydrogen-fueled vehicles commercialize with a fueling
infrastructure that involves tube trailers and/or the use of any other steel
pressure vessels in DOT-jurisdiction applications (which is judged to be
unlikely), then new and specifically focused emergency response resources will be
needed to enable first responders to deal effectively with potential accidents
in environments such as public-access fueling stations.

Discussion of Progress

Progress toward providing the technical basis to support
development of emergency response information applicable to a potential
hydrogen fuel infrastructure involving compressed hydrogen stored in steel
vessels is rated as Addressed, monitoring. This is because considerable
resources are already available, and although these resources were not developed
to apply specifically to environments like public-access fueling stations, it
is unlikely that steel pressure vessels will be a significant element of the
fuel-delivery infrastructure supporting commercialized hydrogen vehicles.

For example, in the DOT ERG2004, compressed hydrogen is assigned
ID Number 1049 and covered by Guide Number 115 (GassesFlammable, Including
Refrigerated Liquids). Emergency response guidance pertaining to tube trailers
(which are designed, manufactured, tested, and marked consistent with DOT-3A or
-33A specifications in 49 CFR 178.36 and 178.37, respectively) that might transport hydrogen is also contained
in literature produced by industrial gas companies (e.g., Safetygrams) and
other sources. Emergency response resources are also readily available for
compressed hydrogen in individual steel cylinders.

In 2005, the NASFM and DOTs RITA established the Hydrogen
Executive Leadership Panel (HELP). HELPs mission is to bring together
emergency responders, government regulators, scientists, consumers and experts
from the automotive and energy industries to facilitate a safe and orderly
transition to hydrogen and other alternative fuel sources. HELP will focus on
issues involved in training, educating, and mobilizing emergency responders to
work with government, industry, and community groups to facilitate and ensure
hydrogen transport, storage and distribution, and the safety of vehicles and
environs.

ASME's Boiler and Pressure Vessel project team on hydrogen tanks
is addressing high pressure gas storage in metal and composite tanks. The work
plan includes a proposed new article KD-10 to Section VIII-3, a code case on
composite tanks for Section VIII-3, and a revision to code case 2390 on metal
lined composite reinforced circumferentially wrapped pressure vessels under
Section VIII-3. Transport tanks may also be included in Section XII.

Recommendations

Currently available emergency response information resources are
adequate for current low-vehicle-number and controlled-access hydrogen vehicle
demonstration projects that sometimes utilize compressed hydrogen delivered in
tube-trailers or individual cylinders. More research is needed to develop
emergency response resources applicable to mobile hydrogen fueling stations
with steel pressure vessels, especially if the use of such mobile fueling
stations increases.

Comprehensive emergency response resources applicable to
compressed hydrogen steel pressure vessels employed as part of a commercialized
hydrogen vehicle fueling infrastructure will probably not be needed, because
steel pressure vessels are not anticipated to be a significant part of the
fuel-transport aspects of such an infrastructure. However, hydrogen fueling
infrastructure evolution should be monitored, and work to develop appropriate
emergency response resources should be initiated if it appears that steel
pressure vessels will in fact be part of this infrastructure.